From New York's favorite and most deluxe living room, the announcer intones, it's another edition of "Radio Deluxe."

"From high atop Lexington Avenue, I'm John Pizzarelli."

"And I'm Jessica Molaskey."

Each weekly edition of the two-hour "Radio Deluxe" program begins just that way. But after that, it's anybody's guess what will be heard next. Terrific music from the Great American Songbook, for sure. Witty stories, certainly. But no consultant-approved playlist and definitely no script. The best jazz is improvised and so, it seems, is the best radio.

"We're here in the 'Deluxe' living room. . . . We're going through sheet music," Pizzarelli, a jazz singer and virtuoso guitarist, told listeners at the top of a recent show.

"We're trying to write our show for the Carlyle Hotel," chimed in his wife, Molaskey, an established Broadway performer and new sensation on New York's cabaret scene. There was the sound of pages rustling, and soon Pizzarelli was introducing an interview with his father, legendary jazz guitarist Bucky Pizzarelli, who described performing for the composer Richard Rodgers years ago at the Pierre Hotel. Molaskey told a story about performing a Stephen Sondheim song at a small party where the guests included, gulp, Sondheim. (He liked her version.)

"Can we get away with playing two tracks?" Molaskey said, as they announced a tune from the CD "A Classy Pair," by Ella Fitzgerald and Count Basie. "It's our radio show, darling," Pizzarelli said.

Indeed it is. Sitting before microphones and dressed to the nines, Pizzarelli and Molaskey are inventing something new by going back to the tried and true: superb music and chatty meanderings about jazz and Broadway, interviews with such performers as Barbara Cook and Peter Cincotti interspersed with the occasional visit from 10-year-old daughter Madeleine, who recently came on to talk about a visit to the Metropolitan Museum of Art.

Onstage and on the air, Pizzarelli and Molaskey, who are both 48, are in the vanguard of a group of 21st-century performers who are lovingly tending the Great American Songbook -- that canon of melodic, literate work assembled more than 50 years ago by George and Ira Gershwin, Cole Porter, Harold Arlen, Richard Rodgers, Lorenz Hart, Johnny Mercer and a few others who helped define an era.

While the songbook grew dusty with the rise of rock and the cultural upheaval that accompanied it, in recent years a new generation has rediscovered the songs of their parents' and grandparents' youth. Performers such as Diana Krall, Harry Connick Jr. and Michael Feinstein have built strong followings by rediscovering and reinterpreting the Greatest Generation's jukebox. Even Rod Stewart found fresh success by recording standards.

But few of the newest performers can match Pizzarelli and Molaskey in musical craftsmanship or in pure, old-fashioned showmanship. They're young, attractive and funny. And, perhaps most important, they are expanding the songbook to include such rock-era voices as Randy Newman, Joni Mitchell and Crosby, Stills, Nash and Young, as well as ambitious new Broadway composers like Adam Guettel.